Heat sensitive audible alarm



y 1957 A. R. CHRISTIE 2,792,801

HEAT SENSITIVE AUDIBLE ALARM I Filed July 21, 1955 IN VEN TOR.

Hazy

, chines.

United States Patent 9 HEAT SENSITIVE AUDIBLE ALARM Alfred R. Christie, Chicago, 11!. Application July 21, 1955, Serial No. 523,484

9 Claims. (Cl. 116-105) This invention relates to a fire alarm device of the detonator or explosive type.

One of the objects of this invention is the provision of an audible fire alarm device which may be manufactured as a complete and inexpensive unit having a fastener such as a screw or nail incorporated therein so that the device may be readily affixed by ordinary means to a wall, support or other structure in the area to be protected.

As a more specific object, this invention seeks the provision of a fire alarm utilizing a heat-sensitive explosive cartridge as the audible signal producing means, and a housing for the cartridge which is sufiiciently strong to resist destruction by the force of the explosion so as to retain therein fragments of the exploded cartridge, but which nevertheless is very inexpensive to make.

As a further object, this invention has within its purview the provision of a cage or housing for an explosive cartridge constituting an audible fire alarm, the cage or housing being made from a closely coiled wire, the ends of the coil being closed on one side by a plate which is mechanically interlocked with the coil and with a fastener for the coil, and the other end of which may be similarly closed off by a plate, or, alternatively, may be closed off by a spiral formed in the end of the coil.

Further objects of this invention are to provide a fire alarm device of the detonator type having provision for applying alabel or other indicia thereto so that those encountering the device in its installed condition may know the nature of the device; the provision of an audible fire alarm of the explosive type which will not injure firemen or other persons standing or working near the device when it goes off; and the provision of a fire alarm of the explosive type which is tamper-proof to prevent children from extracting the explosive cartridge therefrom.

These and other objects of this invention will become apparent from the following detailed description when taken together with the accompanying drawings in which,

Fig. 1 is a perspective view of a preferred embodiment of this invention;

Fig. 2 is a side elevational view of the device shown in Fig. 1;

Figs. 3 and 4 are respectively rightand left-hand end views of the device shown in Fig. 2;

Fig. 5 is an enlarged side elevational view of the device of Fig. 2. in section, showing the interior thereof;

Fig. 6 is a side elevational view, in section, of the device of Fig. 5, the view being taken along line 6-6 of Fig. 5

Fig. 7 is a side elevational view of a modification of the device of Fig. 1;

Fig. 8 is a side elevational view of the modification shown in Fig. 7 looking to the right in Fig. 7; and

Fig. 9 is an enlarged side elevational view of the modification of Fig. 7, said device being shown in section to show the interior thereof.

Referring now to the drawings for a detailed description of the invention and particularly to Fig. 5, the detopating device used to illustrate this invention is depicted therein as a blank cartridge shell 10 ofa size comparable to the .22 gauge rifle bullet shell which is readily available in the open market. Such blank shell is commonly partially filled with an explosive powder and the end 11 thereof is closed by a wad of paper, wax or other relatively soft substance. It is contemplated that when the temperature of the powder within the shell reaches a predetermined value the powder will explode, thereby blowing out the paper or wax 11 and emitting a loud audible sound.

Insofar as the sounding of an alarm is concerned, the shell 10 laid upon any fiat surface, or held against a wall by any suitable strap or adhesive, would be sufiicient. An exposed shell, however, is in itself a hazard either to those working or standing in proximity to the shell at the time it explodes. Furthermore, it is also an attractive nuisance to children who may be tempted to remove the shell and use it as a plaything or toy. It is necessary therefore to surround the shell with a housing which will conceal the shell to avoid its becoming an attractive nuisance, the housing being tamperproof to prevent those knowing of the concealed shell from extracting it from the housing. Additionally, the housing must be sufliciently closely woven to prevent the emission of debris from the exploded cartridge or shell, and lastly, the housing must have suflicient communication from the interior to the exterior thereof to permit the sound of the exploding shell to be heard for the .purpose of sounding an alarm.

Each of the foregoing necessary or desirable qualities for a housing is possessed by the housing shown in Fig. 5 and designated generally by the reference numeral 12. Said housing is comprised principally of a closely coiled wire 13, the coil being a single layer helix of substantially constant diameter throughout the central portion of the housing. One end of the wire 13 is wound into a relatively small diameter substantially flat loop 14 through which may pass the shank 16 of a fastener 15, shown in Fig. 5 as a round headed machine screw.

The left-hand end 17 of the coiled wire 13 as shown in Fig. 5 is similarly coiled into a loop 18 having substantially the same internal diameter as loop 14, said loop 18, however, comprising one turn of a helix which continues for approximately two more turns 19 of a still further reduced internal diameter. It is contemplated that the threaded end 20 of machine screw 15 will fit snugly into the helix 19 so as to be held frictionally in place within housing 12.

It may be noted that the axis of the screw 15 is substantially parallel with the axis of the coiled wire 13 but is displaced laterally therefrom, leaving a space 21 for the reception of the cartridge 10. This eccentric arrangement of the fastener 15 provides ample space for the cartridge within the smallest possible diameter of housing 12 thereby resulting in the use of a minimum amount of wire for the formation of the housing and in a correspondingly low cost thereof.

The reduction in diameter from the diameter of the central portion 13 to the diameter of the loops 14 and 18 results in openings in the ends of the housing through which the shell 10 may be inserted or extracted. Since it is desirable to prevent the extraction of the shell once it is inserted, the ends of the coil 13 are closed by end plates 22 and 23. These plates are preferably made as stampings of sheet metal, but can be made of other ma terial if desired. Said plates are generally circular in outline, plate 22 having an outside diameter slightly greater than the outside diameter of the coil 13 and having an opening 25 through which passes the fastener 15. A notch 26 is formed in the edge region of end plate 22 through which the last coil of the wire housing passes to form the loop 18. Plate 23 is of larger diameter than plate 22 so asto leave a considerable area 27 upontwhich Patented May 21, 1951 fastener 15, and with at 1101111229 through which'the last.

coil of. thehousing-passesZtoform the loop.- 14. r

To assemble the device, ahousing 12-is-selected-1and an endp1ate,.e. g. plate ll isinserted in the place on. the housing. indicated in.- Fig,. 5,. theinsertion. being: accom plished by slidingthe-plate? from the upper outer-regions of the housing ,aswviewed in Fig 5 downwardly, with the notch 26 lowermost; until: said notch straddles the end.

coil of the large diameter portion of the housing. This should result inanautomatic. alignment of openinga25 with the: endhelix.1 9-,.but if suclr alignmentfor any"reajson.-

should? not be had, .plate- 22 is. shifted-transversely -of the 1 diameter of the housing until opening 25 is so aligned. After one end ofthe housing, is: thus closed,- a. blank cartridge: 10: is insertedinto. chamber 21. In a similar manner. end plate23 is insertedlaterally fromthe same upper regions of the-housing, 12. until notch 29 straddles th'eend loop of the? large diameter portion'13. of the hous+- ing, opening. 28\-likewise being shiftedlaterally if necessary until it is aligned with loop 14, opening 25, loop 18 and the. end" helix- 19.

With endplates 22 and 23 in-place, fastener is inserted through the loop 14,, openings-28 and 25, loop 18 and end-helix 1 9'until'thehead of the fastener abuts on loop-14; Subsequentremoval of. the fastener from the housing v12 is prevented by. spot welding the end helix 19 to the screw or fastener 15.

Itimay b'etobiserved thatafter the end helix 19-is welded to fastener 15,. it is substantially impossible to turn end plates 22 and 23- or-to.-remove'them from housing 12. A mechanical interlock is efiectedbetween the fastener, the end plates, and the portions of the coils of the housing passingthrough notches 26 and 29 which holds the assembledparts-of the-device-in fixed relation and makes it possible to handle, ship and install the devices without. fear. of losingthe blank cartridge 10, or of altering thedesigned relationship of the component parts of the device.

When around-heade'dmachine screw is used as a fastening' means, the device issecured to a threaded opening in a-wallor support in a-roorn to be protected simply by turning the head of the fastener 15 until the device is firmly in place; Alternatively, fastener 15 may pass through: a drilled opening in. such wall or support and a npt (not shown) may beuse'd to secure the fastener in p ace.

Theiformshowni inFigs. 7,8 and 9 diifers from the form shown in Figs. 1 to 6 inclusive in that end plate22 isornitted and itsplaceistaken by a spiral formed inthe housing-itself. Thus, as shown clearly in Fig. 9, housing 30 iscomprised of a coil of wire 31 of generally helical shape-to form a substantially cylindrical housing the righthand end of which, as viewed in Fig; 9, terminates in a small loop 32. having'a center disposed eccentrically' of the axis of the cylindrical housing 30: and through which is adapted to pass a wood screw 33-in such manner that the head. 34 thereof bears against loop 32. The said right-'handfendof housing-30' as viewed in Fig. 9 is closed by plate 27- which isinall respects identical with the similarly numberedplate in Fig, 5.

The left-hand end of housing 30 as viewed in Fig. 9 is inserted into housing 39 and plate 27 is then slid transversely of the housing downwardly as viewed in Fig. 9 until the notch 29 thereof straddles the end loop of the coil 31 and the opening 28 is concentric with end loop 32. Wood screw 33 is then inserted through loop 32, opening 28, coil 31 and helix 36 until the head 34 of the screw abuts on coil 32. Helix 36. is then spot welded or otherwise permanently secured to' thescrew 33 and the entire assemblage is= thusfmechani'cally-interlocked-"so that it retains its shape despite relatively rough handling either during shipping or during' the ihstallation of the device.

As in the-Fig. 5 form, the device is: secured. to-a wall or support by turning wood screw 33 until the device is firmly in place.

The spiral must, of course, be of a gradual form to avoid leaving relatively large interstices between successive turns of the spiral. The presence of some openings between. the. successive; turnstof. the spiral. willnot necessarily render the device harmful in. that any debris expelled.

of the device, it is understood. that other heat sensitive noise producing, devices. triggered by attaining a predetermined temperature may be. substituted for the blank cartridge described above. It. is. also understood. that in place of the screws. showninthe Fig. 5 and Fig. 9 modifications an ordinary. nailimay be used, the device then being. applied to.a.wall.-or. support by hammering, thenail into the. support. It. is understood further that.the-fore.- going descriptioniis merely illustrative of. preferred cmbodirnents of the invention. and that'the. scope of the invention therefore is not to. be limitedthereto. but is to be determined by the appended claims.

. I claim:

l. Ahousing for a heat sensitive audible alarm device including an elemen'tl adapted to emit a noise upon attaining. a predetermined temperature, said housing. comprising a coil of wire, the ends of the coil being of reduced diameter withrespecttothe central portion of the coil,.means forclosingoneend of'said coil, and a fastener passing through the reduced. diameter ends and through the closing means,;saidfastener. extending beyond the coil endopposite the closing means, and. means. for securing'the coillto the fastener, said. extending end of the fastener beingadapted. to. be secured'to a wall or the like.

2 A housing for. a heatse-nsitive audible alarm. device includingan elementadapted' toemita. noise upon attainin-g'a predetermined temperature,.said housing. comprising a single piecethelix of wire, the. endsof the helix being of reduceddiameter an'd'havingtheir centers. displaced transversely of the axis of the helix, plate means. closing one end of. said coil, and a fastener passing through. the reduced diameter ends of the coil and through the closing means, said fastener extending beyond the coil and opposite the closing means, and means for securing the coil to the fastener, said extending end ofthe fastener being. adapted to be secured to a wall or. the like.

3. A "housing for a heat sensitive audible alarm device as described" in claim 2 said'plate having a notch in the side thereof disposed substantially diametrically opposite the fastener, said notch being adapted to receive a portion of the wire of the helix and to permit the helix to cross over from one. side of the plate-to the other, said notch and fastener serving; to" form amechanicalinterl'ock between the plate,..-fastener: and helix.

4.. Ahousingfc'raheat sensitive; audible: alarm device including an element adapted touemita noise upon-attain inga predetermined temperature, said housingcomprising a helical coilof wire, the'end's of the helix'bein'g erreducedi diameter; plate means for closingbothendS of said coil, and a fastener passing through the reduced diameter ends of the coil and through both closing means, said fastener extending beyond one of said coil ends, and means for securing the coil to the fastener, said extending end of the fastener being adapted to be secured to a wall or the like.

5. A housing for a heat sensitive audible alarm device as described in claim 4, one of said plate means being circular in outline and having a diameter substantially equal to the outside diameter of the coil and the other of said plate means having a portion extending radially outwardly beyond the helix to provide space for the reception of printed matter.

6. A housing for a heat sensitive audible alarm device as described in claim 4, each said plate means having a notch in the side thereof disposed substantially diametrically opposite the fastener, each said notch being adapted to receive a portion of the wire of the helix and to permit the helix to cross over from one side of the plate to the other, said notch and fastener serving to form mechanical interlocks between the plates, fastener and helix approximately the same area as the area of the end of the helix and the other being of larger area and being adapted to receive identifying data.

7. A housing for a heat sensitive audible alarm device including an element adapted to explode upon reaching a predetermined temperature, said housing comprising a coil of wire having spaced ends of reduced diameter relative to the diameter of the coil, said coil having a region of progressively smaller turns connecting said coil to one of said end regions such that the said end of the coil having the progressively smaller turns is substantially synaeot closed by said progressively smaller turns, plate means for closing the oposite end of said coil, and a fastener passing through the reduced diameter ends of the coil and through the plate means, said fastener extending beyond the coil end opposite the closing means, and means for securing the coil to the fastener, said extending end of the fastener being adapted to be secured to a wall or the like.

8. A housing for a heat sensitive audible alarm device including an element adapted to explode upon reaching a predetermined temperature, said housing comprising a helical coil of wire, the ends of the helix being of reduced diameter, means for closing one end of said coil, and a fastener passing through the reduced diameter ends of the coil and through the closing means, said fastener having a head thereon adapted to overlie the end of the coil adjacent thereto, said fastener extending beyond the coil and opposite the closing means, and means for securing the coil to the fastener, said extending end of the fastener being adapted to be secured to the wall or the like.

9. A housing for a heat sensitive audible alarm device as described in claim 8, said means for closing one end of said coil comprising a plate inserted between the reduced diameter end of the helix adjacent the head of the fastener and the coil of the helix adjacent thereto.

Martin July 8, 1924 Kalstrom Oct. 27, 1936 

